NFL teams seeking offensive line help - and in reality, all 32 teams are always looking for more bodies in the trenches - can enter the draft eager or apprehensive, depending on which position is most critically needed.

If you want a premier offensive tackle, you'll have to grab him near the top of the first round.

On the flip side, talented interior linemen are available in abundance in this group. Center Ryan Kalil (USC) and guard Ben Grubbs (Auburn) could be drafted in the first round. But teams shouldn't reach for an interior lineman - depth at center and guard will likely extend into the second day of this draft.

The pickings at tackle will become slim after the early stages of the first round. Wisconsin's Joe Thomas and Penn State's Levi Brown are expected to be chosen among the first 10 picks. Thomas is considered by many to be one of the draft's few sure things.

Once Brown comes off the board, only two other tackles are considered a cinch to be taken in the next 50 picks and the majority of the middle-round prospects are developmental types.

An in-depth look at the best offensive linemen:

TACKLES:

1. Joe Thomas, Wisconsin, 6-7, 311, SR

The elite pass blocker in this draft, Thomas is the kind of physical prototype at left tackle every NFL team wants on its roster. Thomas signed as a tight end and also played defensive end as a freshman before emerging as Wisconsin's starting left tackle as a sophomore. Blessed with elite foot quickness, balance and long arms, Thomas would have been selected in the first round of the 2006 draft had he elected to leave school early. The decision was largely made for him when he tore the ACL in his right knee while playing on the defensive line in Wisconsin's 2006 bowl game against Auburn.

Remarkably, Thomas' pass-blocking prowess improved his senior season while battling back from the injury suffered only months earlier. Thomas had graded out at 87.1 percent as a junior, giving up only four sacks. He improved to 92 percent in 2006, when he was assigned partial blame for one sack despite facing a Big Ten conference blessed with several elite pass rushers. A gifted all-around athlete, Thomas participated in track and field in 2004 and 2005, setting the school indoor record for the shot put. Thomas has the combination of size and athleticism to eventually be a Pro Bowl tackle. Those worried about the RobertGallery comparisons should note the mental toughness Thomas displayed in his remarkable recovery from a serious knee injury. With the exception of Calvin Johnson, there isn't a talent in the draft who is as much of a sure thing as Thomas.

2. Levi Brown, PennState, 6-6, 323, SR

As dominant as Thomas is as the nation's top pass blocker, Brown may be the draft's top run blocker by the same margin. Blessed with great size and explosiveness, Brown is able to physically manhandle opponents while also showcasing the rare agility to block on the move. He shows strong hands to jolt the pass rusher off the snap and has the rare patience to force the defender to commit to his rush. Has the long arms to keep defenders at bay and has allowed only a combined four sacks over the past two seasons despite the Big Ten's impressive assortment of pass rushers. Wasn't his typically dominant self at times in 2006, though this may have been the result of returning too soon from a torn knee meniscus suffered in late September. Despite starting 45 games at PennState (44 at left tackle) Brown wanted to answer any questions about his health and chose to play at the Senior Bowl. There, he proved himself to be the top offensive lineman in Mobile and legitimized his status as a likely top-10 pick.

3. Joe Staley, Central Michigan, 6-6, 306, SR

Since signing with Central Michigan as a 220-pound tight end, Staley grew into a 306-pound left tackle whose unparalleled athleticism has drawn the attention of many NFL offensive line coaches. A 39-game starter for the Chippewas, Staley never missed a game due to injury. He was the starter at left tackle each of the past two seasons and surrendered five total sacks during that time, grading out at 84-percent effectiveness. Scouts wondered about Staley's level of competition in the MAC - Staley's biggest threat was arguably teammate Daniel Bazuin. A strong performance when pitted one-on-one against top defenders at the Senior Bowl, however, began to open scouts' eyes to Staley. An impressive Pro Day performance has boosted his stock even higher. With reports of Staley running in the 4.7s before his senior season circulating throughout the league, expectations were high entering Staley's workout. The Pro Day performance he had for scouts was one for the ages. Staley's 40-yard dash (4.80), shuttle (4.30), and three-cone drill (7.17) were each the fastest recorded by an offensive lineman in the 2007 draft class.

4. Tony Ugoh, Arkansas, 6-5, 301, SR

Ugoh is a talented athlete who stepped up his play as a senior and emerged as one of the elite offensive linemen in the country. A three-year starter at left tackle with a career mark of 87-percent blocking effectiveness, Ugoh allowed only one sack as a senior, earning first-team All-SEC honors. Ugoh was part of a front five that was generally responsible for a dominant rushing attack that averaged 228.5 yards per game and ranked fourth in the nation. At the Senior Bowl, Ugoh was exposed a bit. While he has a strong hand punch and shows good lateral quickness, he doesn't use either with enough regularity. He has good footwork and can be a difference-maker in the running game due to his upper-body strength, but he may lack the consistency to remain on the outside. A move inside to guard could be in Ugoh's future.

5. Doug Free, Northern Illinois, 6-6, 324, SR

Free is an underrated prospect whose struggle with an undiagnosed stress fracture in his right foot early in the season caused him to fall down some draft boards. The injury forced Free to wear a protective boot and miss practice for much of the 2006 season, limiting his overall effectiveness. Still, he was recognized for the second consecutive season as a first-team All-MAC selection and was graded at 91 percent for the regular season. Free did appear to be fully healthy at East-West Shrine practices.

A four-year starter for the Huskies, Free has been lauded by his coaches. Monte Clark, who helped coach the offensive line at the East-West Shrine Game and more famously was a former NFL head coach, gushed about Free's performance, as has NIU head coach Joe Novak. Novak characterizes Free as "a lot better athlete" than Ryan Diem, a former NIU player under Novak, who plays right tackle for the Colts.

6. James Marten, BostonCollege, 6-8, 309, SR

In a draft in which pure prospects at right tackle are few, it could be up to a player who first played the position in his final collegiate game to lead the charge. A left guard before he was asked to move to the all-important left tackle position as a senior, Marten likely will play right tackle in the NFL. Though Marten allowed only 1 1/2 sacks in his only season at left tackle, he lacks great footwork and balance. Used at right tackle at the Senior Bowl, Marten showed a strong hand punch and the physicality teams want on the right side.

Other Potential Impact Tackles:

-- Marshall Yanda, Iowa, 6-4, 307, SR: A junior college transfer who showed significant improvement throughout his career but might best fit at guard, especially early in his career.

-- Ryan Harris, Notre Dame, 6-5, 305, SR: Four-year starter who should be a tougher, stronger, more polished player at this point.

-- Allen Barbre, Missouri Southern State, 6-4, 300, SR: Raw talent with the quick feet and upper-body strength scouts are looking for but he's likely a second-day pick based on questions about the level of competition he faced.

-- Mike Otto, Purdue, 6-5, 308, SR: Underrated prospect who shows the footwork and strength to surprise as a left tackle at the next level. Not a special talent, but reliable.

GUARDS:

1. Ben Grubbs, Auburn, 6-3, 311, SR

Originally signed as a defensive lineman, Grubbs made the transition to tight end before settling in at guard for his final 32 games. Considered the top pure guard prospect, Grubbs shows a rare blend of power, intensity and athletic ability that hasn't been seen in the SEC since Alan Faneca suited up for LSU. Despite his strong standing with NFL teams, Grubbs elected to participate in the Senior Bowl and established himself as not only the top guard, but one of the elite offensive linemen in the draft.

2. Justin Blalock, Texas, 6-3, 320, SR

Recognized as the inaugural winner of the Big 12's Offensive Lineman of the Year, Blalock has been a model of durability, consistency and versatility for the Longhorns. A veteran of a school-record 51 consecutive starts during his career, Blalock spent most of his career at right tackle before moving inside to right guard midway through his senior season. A punishing drive blocker, Blalock has the quickness to block on the move and left Texas with a string of 27 consecutive games without allowing a quarterback sack. Lining up at both right tackle and right guard while at the Senior Bowl, Blalock's lack of balance and agility caused him some trouble when pitted against speedy pass rushers. If moved permanently inside, Blalock could be on the verge of a standout career in the NFL.

3. Arron Sears, Tennessee, 6-3, 319, SR

Arguably the most versatile offensive lineman in the 2007 draft, Sears, a veteran of 37 starts for the Vols, started at left tackle (26), right tackle (six), left guard (one) and right guard (five) throughout his career. He may lack the size and quick kick-slide to remain at left tackle, where he played as a senior, but he could be a standout guard early in his NFL career. There are few players in this draft with a better combination of straight-ahead blocking in the running game and the devastating hand punch to control his man as a pass blocker. In 2006, Sears earned All-American and All-SEC recognition.

4. Manuel Ramirez, Texas Tech, 6-3, 326, SR

A four-year starter for the Red Raiders at right guard, Ramirez isn't your typical Texas Tech offensive lineman. Given head coach Mike Leach's pass-happy offensive system, scouts have come to identify Tech as a hot bed for quick-footed pass blockers. While Ramirez is surprisingly nimble for a player of his dimensions, his best asset is his pure power. His 550-pound bench press is a school record and Ramirez seems best suited to a straight-ahead run blocking scheme than the pass-happy Texas Tech offense.

Ramirez tied with Texas offensive guard prospect Justin Blalock with a Scouting Combine-leading 40 reps of 225 pounds. Ramirez is known for his intelligence. He called all the line's blocking schemes the last two years and served as the primary mentor for younger players. He led a blocking unit that reduced the team's total of sacks allowed from 36 in 2005 to 19 in 2006.

5. Andy Alleman, Akron, 6-4, 305, SR:

Thought by some to be on the verge of establishing himself as an up-and-coming defensive end with Pittsburgh, Alleman elected to transfer to Akron to pursue an opportunity to play at a position he felt his size and athleticism might better translate. Alleman proved right, quickly establishing himself as one of the best drive blockers in the MAC. Known for the intensity of his off-season training regimen, he set numerous Akron lifting records (465-pound bench press, 595-pound squat).

A starter in 24 of 25 games while at Akron possessing good strength, size, and overall athleticism for the guard position, Alleman nonetheless remains a work in progress with legitimate upside.

6. Josh Beekman, BostonCollege, 6-2, 313, SR

Shorter than scouts would like and not necessarily the nimble athlete needed to fit every scheme, Beekman's explosive drive blocking and consistency in protecting the quarterback rank him among the draft's top interior linemen. In starting 36 of Boston College's last 38 games, Beekman has never allowed a quarterback sack. Continuing the BostonCollege tradition of producing fine offensive linemen, Beekman was recognized as the Golden Eagles' first winner of the ACC's Jacobs Blocking Trophy in 2006, the award given annually to the ACC's top lineman. While scouts admire his strength and use of his natural leverage advantage when run blocking, Beekman lacks agility and struggles blocking on the move. He may ultimately be destined to play center.

-- Mike Jones, Iowa, 6-5, 309, SR: Former offensive tackle who blossomed once he slid inside to guard and could continue to improve with more time inside, where his lack of athleticism can be protected.

-- Cameron Stephenson, Rutgers, 6-3, 306, SR: A juco transfer who switched from offensive tackle to defensive tackle and then to guard over the past two years. He's raw but has upside.

CENTERS:

1. Ryan Kalil, SouthernCalifornia, 6-3, 299, SR

As technically sound as any center prospect the NFL has seen in some time, Kalil gets away with limited size and overall strength with technical excellence. He's a legitimate first-round prospect at center, a position that rarely sees players earn such acclaim.

Kalil began a string of not allowing a quarterback sack or pressure in his final 26 games. A unanimous choice for All-Pac-10 Conference first-team honors, Kalil was named winner of the Morris Trophy, given to the league's top offensive lineman, as voted by the Pac-10's defensive linemen. Despite his status as the elite center prospect in the draft, Kalil played in the Senior Bowl and further proved his ability. While bigger, stronger nose guards are capable of occasionally giving him trouble, Kalil's tenacity, technique and underrated athleticism make him consistently effective against even the best talent.

2. Samson Satele, Hawaii, 6-3, 300, SR

A starter in all 53 games of his career, the longest such streak enjoyed by any collegiate player as of the end of the 2006 season, Satele is one of the draft's most underrated performers. Having started at left tackle, left guard and center throughout his career, Satele is not only one of the more versatile linemen in the draft, he is one of the most accomplished, allowing a combined two sacks over the past two seasons (none as a senior).

What's even more impressive is that he held his primary assignment without a tackle in seven of this season's 14 games, a remarkable achievement considering this was Satele's first season at center. So much of a standout at left guard that he considered leaving school early, Satele returned and volunteered to move to center to help the team. He was named All-WAC first-team and produced 65 knockdowns for an offense that generated 559.2 yards per game and 84 touchdowns. Satele has an impressive hand punch and generates movement consistently. With his raw power and nimble feet, pro scouts are comparing him to former San Francisco 49ers great Jesse Sapolu.

3. Dustin Fry, Clemson, 6-3, 315, SR

For teams looking for a dominant drive blocker in the middle, Dustin Fry is a perfect fit. Among the strongest players in the country, Fry holds the school record with a 500-pound bench press. His hand punch and use of leverage make him quite effective at knocking defenders to their seat, registering an impressive 171 knockdowns while manning the pivot over the past three seasons. A full-time starter the past two years, Fry helped Clemson develop into the nation's fifth-best rushing team, averaging 217.85 yards per contest on the ground last season. Fry has been able to control the line of scrimmage with his strength at the college level, but must develop better hand placement. Though quick off the snap, he lacks agility and is best in an offense that allows him to block straight ahead, rather than on the move.

Other Potential Impact Centers:

-- Doug Datish, Ohio State, 6-4, 302, SR: Versatile lineman with starts at tackle, guard, and center with the Buckeyes. He could develop significantly if allowed to hone his craft at one position.

-- Leroy Harris, North Carolina State, 6-3, 302, SR: Effective due to his combination of quickness and technique, Harris could drop a bit due to lingering durability issues.